What symptoms would a stuck theromstat cause in a standard carb 1.6 engine? What long term damage would this cause if it was left like this with a stuck thermostat? Would a stuck thermostat explain quite lot drop of power, have to rev it to death to get a high speed or maintain one? eg at traffic lights you have to keep reving it otherwise will cut out.
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normal symptoms of a knackered thermostat are either overheating, or overcooling. If it's ye olde thermostat the temp gauge should tell you in a matter of seconds.
The symptom of a knackered thermostat is overheating.
The symptoms you describe are those of a knackered head gasket. A compression test will prove or disprove this.
Of course the head gasket may have failed due to the overheating caused by a knackered thermostat.
Steve
Well the temperature gauge gas never registered as over heating. It hasn't been reaching where it should be. Which would seem like 'overcooling'. Engine always seems to be running as if the choke is on all the time.
Wouldnt a failed head gasket mean significant loss of coolant in the radiator? As that hasn't happened.
More like the distributor vacuum advance is stuck or diaphragm or hose has a leak. Pull hose that leads from distributor to carb off at carb end. Wipe clean and suck on it. If you can create suction the hose and diaphragm are ok. If you can suck air it's leaking somewhere, check hose first and if ok replace vacuum capsule. Beware, main dealers tend to sell compete distributors, go to a good motor factor (yellow pages or yell), else you are going to tour the scrap yards but the diaphragms on the cars there are all dud or about to fail too. If you can create suction you should hear a soft clunk from the distributor as you release it - that's the advance plate returning under spring action. If no clunk take the rotor cap off and check the plate with the arm attached rotates when you push the arm into the vacuum capsule. A squirt of WD40 should help.
Are you checking radiator top tank or just the expansion tank? Temp gauge should come up to midway in about 2 miles of steady 30mph driving. If it reads low it's either a stuck open stat or the sensor is in air.
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If your 1.6 has an water heated auto choke, and the thermostat is stuck wide open- the overcooling could result in the auto choke getting only cold water so never opening- and causing a rich mixture which would give you a fast idle, poor mpg at the least. Some auto chokes lock the 2nd barrel shut whilst in use- which would restrict power to about 50%.
Long term damage of running very cool and / or with the choke stuck on would be bore wash and knackered rings leading to poor compressions and sump oil dilution, and in its worst possible case bearing failure because the oil has been thinned by fuel.
A total cut when it approcahes idle, rather than a splutter splutter stall would be a blocked idle circuit in the carb.
Tim..
It is more of a splutter splutter stall. Can be tricky when braking in traffic as you have to quickly touch break then apply revs again.
MPG does seem to be poor. It does seem to have started leaking more oil than normal. Would this indicate anything?
I checked the top tank. It needed about half a litre of topping up. But is months since I last topped it up. Has been needing this kind of topping up for a long time. i dont know why it loses half a litre over a few months of constant use, but apart from that no major problems.
Are these repairs likely to be costly? How much labour time. Its the labour that bumps up the cost a lot, even if the parts that are needed are cheap.
Some systems require that bleed points are opened. French cars can have up to 3 bleed points, most have 2. Some are simple pressure caps like tyre valves others are hex cap screws with copper washers. Some are easy to see like the Pug 1.1 where one is on the heater feed and one on the stat housing. Some are almost impossible to get at like the BX16 where one is hidden at the back of the engine below the exhaust manifold. Have to be filled though an extension on the rad filler point to get the head of water needed to drive all the air out.
Small leak on a hose somewhere - one of the small ones that feeds the heater or part of the manifold etc would be a trace of blue scale from antifreeze at the leak. Cracked head? Need to have a cylinder leakage test and cooling system pressure test to find out for sure where the water is going and why. Compression test just won't show this slow leakage.
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Exactly what 1.6 is it?
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